title: Adult epicardial fat exhibits beige features.
abstract: BACKGROUND
  Human epicardial fat has been designated previously as brown-like fat. The supraclavicular fat depot in man has been defined as beige coexistent with classical brown based on its gene expression profile.
  
  
  OBJECTIVE
  The aim of the study was to establish the gene expression profile and morphology of human epicardial and visceral paracardial fat compared with sc fat.
  
  
  METHODS
  The study was conducted at a tertiary care hospital cardiac center.
  
  
  METHODS
  Epicardial, visceral paracardial, and sc fat samples had been taken from middle-aged patients with severe coronary atherosclerosis or valvular heart disease.
  
  
  METHODS
  Gene expression was determined by reverse transcription-quantitative PCR and relative abundance of the mitochondrial uncoupling protein-1 (UCP-1) by Western blotting. Epicardial tissue sections from patients were examined by light microscopy, UCP-1 immunohistochemistry, and cell morphometry.
  
  
  METHODS
  We hypothesized that epicardial fat has a mixed phenotype with a gene expression profile similar to that described for beige cell lineage.
  
  
  RESULTS
  Immunoreactive UCP-1 was clearly measurable in each epicardial sample analyzed but was undetectable in each of the 4 other visceral and sc depots. Epicardial fat exhibited high expression of genes for UCP-1, PRDM16, PGC-1α, PPARγ, and the beige adipocyte-specific marker CD137, which were also expressed in visceral paracardial fat but only weakly in sternal, upper abdominal, and lower extremity sc fat. Histology of epicardial fat showed small unilocular adipocytes without UCP-1 immunostaining.
  
  
  CONCLUSIONS
  UCP-1 is relatively abundant in epicardial fat, and this depot possesses molecular features characteristic of those found in vitro in beige lineage adipocytes.
authors.affiliation: VA Greater Los Angeles Healthcare System, Endocrinology and Diabetes Division 111D, 11310 Wilshire Boulevard, Los Angeles, California 90073, USA. hsacks@hotmail.com
authors.forename: Harold S
authors.initials: HS
authors.lastname: Sacks
authors.forename: John N
authors.initials: JN
authors.lastname: Fain
authors.forename: Suleiman W
authors.initials: SW
authors.lastname: Bahouth
authors.forename: Shalini
authors.initials: S
authors.lastname: Ojha
authors.forename: Andrea
authors.initials: A
authors.lastname: Frontini
authors.forename: Helen
authors.initials: H
authors.lastname: Budge
authors.forename: Saverio
authors.initials: S
authors.lastname: Cinti
authors.forename: Michael E
authors.initials: ME
authors.lastname: Symonds
mesh_terms: D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000368:Aged; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D006801:Humans; D050152:Intra-Abdominal Fat / Q000378:metabolism*; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism; D010496:Pericardium / Q000378:metabolism*; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D053261:Tumor Necrosis Factor Receptor Superfamily, Member 9 / Q000235:genetics / Q000378:metabolism; D000071256:Uncoupling Protein 1
chemical_list: D004268:DNA-Binding Proteins; D007473:Ion Channels; D024101:Mitochondrial Proteins; D047495:PPAR gamma; C486497:PPARGC1A protein, human; C416371:PRDM16 protein, human; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D014157:Transcription Factors; D053261:Tumor Necrosis Factor Receptor Superfamily, Member 9; C000604371:UCP1 protein, human; D000071256:Uncoupling Protein 1